Chosen Solution

well, I would like to know how it can be possible if I want to flash my iphone. As I heard this hast to be set on DFU mode. could u plz tell me how to do it? and what should I do afterwards? tnx

You can put your iphone in DFU mode ready to be reset/restored by iTunes. You must first turn your phone off (Holding down power button and sliding the x over). Only connect your usb lightning cable to your computer. Hold down the home button as you plug in the USB lightning cable to the phone. After the cable photo is displayed on the iphone, the phone is ready to take a restore from itunes on the computer.

By flash do you mean jailbreak?